Cost to convert a room back into the garage?

Hi -- can anyone give a ballpark estimate of the cost and issues involved with taking a room - that was once the garage but now a room - and turning it back into a garage? I'm looking at a house that the previous owner added a 4th bedroom by closing off the garage. Every house in the neighborhood has a 2 car garage and I really think the house needs the garage -even at the expense of the floor space.

The front has brick now. they did a nice job except for leaving the driveway there. All of the houses in the neighborhood are similiar -- and they all have 2 car garages. I'll see if I can post a picture...